1. Field of the Invention
The present invention relates to flash memory device, and more particularly to flash memory device with Universal Serials Bus (USB) plug.
2. Description of Related Art
A flash memory device, like a portable hard drive, is composed of a controllable and memorizable electronic circuit board for accessing data files. Universal serial bus (USB) is standard by the USB Implementers Forum (USB-IF), an industry standard body incorporating leading companies from the computer and electronic industries. USB is widely used to connect peripherals such as digital cameras, printers, external storage, networking components, etc. USB plug is assembled on the flash memory device for connecting with various peripherals. The USB plug connects with an end of the electronic circuit board and presents as a transfer interface between the electronic circuit board and a matrix (like a computer system). The flash memory device further comprises a case for protecting the electronic circuit board from dust and humidity. The USB plug extends out of an opening of an end of the case.
With rapid development of electronic industry, USB 2.0 was standardized by the USB-IF at the end of 2001. The speed rate of USB 2.0 is up to 480 Mbit/s (60 MB/s). Though Hi-Speed devices are commonly referred to as “USB 2.0” and advertised as “up to 480 Mbit/s”, not all USB 2.0 devices are so Hi-Speed. Hi-Speed devices typically only operate at half of the full theoretical (60 MB/s) data throughput rate. However, under a circumstance transmitting an audio or video file, which is always up to hundreds MB, even to 1 or 2 GB. As a consequence, fast serial-bus interfaces are being introduced to address different requirements. PCI Express, at 2.5 GB/s, and SATA, at 1.5 GB/s and 3.0 GB/s, are two examples of High-Speed serial bus interfaces.
However, these non-USB protocols are not used as broadly as USB protocols. Many portable devices are equipped with USB interfaces other than these non-USB interfaces. One important reason is that these non-USB interfaces contain a greater number of signal pins than an existing USB interfaces and are physically larger as well. USB include four pins such as power, ground and serial differential data D+, D− pin. While the PCI Express is a 26-pin interface and wider card-like form factor limit the use of Express Card, the SATA uses two connectors, one 7-pin connector for signals and another 15-pin connector for power. The existing USB interfaces have a small size but low transmission rate, while other non-USB interfaces have a high transmission rate but large size. Neither of them is desirable to implement modem high-speed, miniaturized electronic devices and peripherals. To provide a flash memory device with a kind of plug which has a small size and a high transmission rate for portability and high data transmitting efficiency is much desirable.
Hence, a flash memory device with a kind of interface with a small size and a high transmission rate is needed to solve the problem above.